Cardiovascular Complications Flashcards
what are the common complications related to:
- heart rate
- blood pressure
- volume
Heart rate:
- tachycardia
- bradycardia
- arrhythmias
Blood Pressure:
- hypertension
- hypotension
Volume:
- hypovolemia
- hypervolemia
what are some considerations with heart rate
- age of animal
- size/breed of animal
- resting HR
do adults or neonates have a higher HR and why
neonates:
- immature SNS
- increased metabolic rate
CO =
BP =
CO = HR x SV
BP = CO x SVR
what influences stroke volume
preload, afterload, contractility
what influences oxygen delivery
- cardiac output
- oxygen content
- also ETCO2 (indicates O2 consumption and CO2 production in tissues)
what is bradycardia
slow heart rate
what are the consequences of excessively low HR (bradycardia)
will directly lower CO and BP
(since co = HR x sv and bp = CO x svr)
bradycardia is a consequence of increased _____________ activity
parasympathetic
what are the 3 broad causes of increased parasympathetic tone (and thus bradycardia)
1) increased vagal tone
2) drug-induced
3) reflex mechanism due to hypertension
what are causes of:
1) increased vagal tone
2) drug induced bradycardia
3) reflex bradycardia from hypertension
1) oculocardiac reflex (eye surgery), GI pressure, during expiration
2) alpha-2 agonists, opioids
3) alpha-2 agonists, Cushing reflex (increased intracranial pressure), primary hypertension
besides increased parasympathetic tone, what are 3 other causes of bradycardia
1) hyperkalemia
2) hypothermia
3) cardiac disease (sick sinus syndrome)
when do we treat bradycardia
- if marked
- if hypotension or low CO is associated
- if markedly irregular and/or dysrhytmias are also present
how do we treat bradycardia caused by:
- increased vagal tone
- drug induced
- reflex mechanism for hypertension
- cardiac disease
- increased intracranial pressure
- hyperkalemia
- hypothermia
- increased vagal tone: ANTICHOLINERGIC
- drug-induced: REVERSAL, LIDOCAINE, ANTICHOLINERGIC (if not hypertensive)
- hypertension: CONTROL HYPERTENSION
- cardiac disease: ANTICHOLINERGICS, ISOPROTERENOL, PACEMAKER
- increased ICP: CONTROL ICP
- hyperkalemia: DECREASE K+, CALCIUM GLUCONATE
- hypothermia: WARM
what is tachycardia? what are the consequences
fast HR;
- increased CO
- increased BP
- decrease SV if too fast
- increased O2 consumption by myocardium can cause myocardial ischemia and arrhythmias
in general, tachycardia is caused by increased __________________ activity
sympathetic
what are examples of conditions that increase sympathetic activity, leading to tachycardia
- light anesthetic plane/pain
- hypotension/hypovolemia (reflex)
- hypercapnia/hyperthermia
- drug induced
- hypoxia/shock
- specific diseases
what are examples of drugs that cause tachycardia
ketamine, sympathomimetics, anticholinergics
what are examples of specific diseases that cause tachycardia
- pheochromocytoma
- hyperthyroidism
- heart disease
how do you treat tachycardia caused by the following:
- light anesthetic plane/pain
- hyperthermia/hypercapnia
- hypotension/hypovolemia
- hypoxia/shock
- specific diseases
- drugs
- light anesthetic plane/pain: CHECK DEPTH/ANALGESIA
- hyperthermia/hypercapnia: COOL DOWN/VENTILATE
- hypotension/hypovolemia: FLUIDS/SYMPATHOMIMETICS
- hypoxia/shock: FLUIDS, IONOTROPES
- specific diseases: ADDRESS
- drugs: STOP GIVING
what do we look for when diagnosing dysrhythmias
- all waves present (P, QRS, T)
- all P associated with a QRS
- note rhythm
- heart rate
what is by far the most common dysrhythmia diagnosed during anesthesia
AV block
what is going on during AV blocks
conduction from the atria to ventricles is impaired (P and QRS no longer associated)
what is commonly associated with AV blocks (tachycardia or bradycardia)
bradycardia
